Ventilation of dynamoelectric machines



Dec. 14, 1954 A. WENDEL 2,697,179

VENTILATION OF DYNAMOELECTRIC MACHINES Filed March 11, 1952 4Sheets-Sheet 2 Q1 5 It Ill lgglll' g .LOIGTI/ Alma-mil 1mm: 5

Dec. 14, 1954 L. A. WENDEL 2,697,179

VENTILATION OF DYNAMOELECTRIC MACHINES Filed March 11. 1953 4sheets-sheet :s

j'rwzmlaz LOWE? A Wendei 8 mmV/\ 7/ tumm Dec. 14, 1954 A. WENDELVENTILATION OF .0 Filed March 11. l952 YNAMOELECTRIC MACHINES 4Sheets-Sheet 4 Elwyn L32 W .WendeZ F A Fwew u may United States PatentOffice VENTILATION F DYNAMOELECTRIC MACHINES Lorenz A. Wendel,Somerville, N. J., assignor to The Singer Manufacturing Company,Elizabeth, N. J., a corporation of New Jersey Application March 11,1952, Serial No. 275,894 4 Claims. (Cl. 31062) Motors of this generaltype are characterized by having ilanges for mounting on thedrying-chamber wall and havmg a motor-bearing support located wellWithin the chamber.

ad for a more complete understanding of the problem involved.

end-cover at the driving end of the motor comprises an outer flangedbonnet efine circumferentially-spaced longitudinal intake ductsconnected to the atmosphere through openings adjacent the flange. Air isdrawn in through the intak and flows to the inner end of the b statorring.

he difiiculty with this arrangement as an effective means of cooling thebearing, lies in the fact that the entering air travels for someconsiderable distance through the intake ducts in good heat transferrelation with the bearing housing is considerably hotter than theambient temperature and thus less able to reduce the bearingtemperature.

heretofore.

With the above and other objects in view,

inafter appear, the invention comprises the devices, com- In thedrawings: Fig. l is a longitudinal section taken through a motorembodying the invention.

ig. 2 is a longitudinal elevation, :howing the motor of Fig. 1 in normal)perating inside a drying chamber.

partly in section, use driving a fan 2,697,179 Patented Dec. 14, 1954Fig. 3 is an enlarged transverse section taken on line 3-3 of Fig. 1.

Fig. 4 is tion, looking into th on the line 4-4 of Fig ig. 5 is an endelevation view of the motor of Fig. 1

opposite elevation view, partly in sec detached end-cover approximately1.

carrying a stator winding 12.

rotor core 13 secured squirrel-cage winding 15 blades 16 n end-cover 17is tured portions 18 which serve as ventilating air inlet ings andsurround a central hollow boss 19 adjacent baffle ring 24 which isgenerally conical in shape and inwardly constructed contact with thestator core 11.

At the driving end of the machine 26 formed at the end nearest thestator frame with an external flange ring verse wall 28 havingcircumferentially spaced air 2 best in Fig. 3. flange end of theend-cover 26 e central end by hearing with said adverse travel thebearing 31 position.

It will be seen that through the into the end-cover 26 and are providedwith nuts 44 for securing the sembly.

away from when the motor 1s operated in a vertical behind the statorcore 11 and once, 1nto the space within the end-cover 26 From here theair is drawn y the fan 37 its passage through the space 36) until'afterit has combearing support, an outer cylindrical portion radially pletedits function of cooling the motor and its associated spaced from andcompletely enclosing said inner portion parts, particularly the bearing31 which is especially diffito form therewith a generally annularenclosure accescult to cool on account of its position well within thesible from Within said inner portion through said ventioven latingducts, said outer portion being secured to said Referring to Fig. 2,there is shown a motor of the inner portion along a circumferentialjoint adjacent said type described above, mounted in the wall 45 of adrying flange, and ventilating ducts formed in said inner portionchamber or oven and connected to drive an impeller adjacent said flangeand radially inside the circumference wheel 47 for circulating the hotair within the chamber. of said joint but radially outside saidventilating ducts A heat shield 43 is employed to partially divert thecirl0 surrounding the bearing support to provide communicaculation ofhot air in the chamber away from the cover tion between said enclosureand the atmosphere. 35, thereby to lighten the burden on the coolingsystem 3. In a dynamoelectric machine of the open-frame of the motoritself. It will be appreciated that the ventitype, an end-cover securedthereto, a bearing supported lating problem is made more severe becausea very large centrally in said end-cover, a shaft journaled in saidportion of the motor is located inside and exposed to bearing, a firstgroup of ventilating ducts located in said the heat of the oven in orderto provide bearing support end-cover adjacent to said bearing and givingaccess to very close to the impeller. the interior of said end-cover, anexternal shell secured Fig. 6 illustrates a modification of the motor ofFig. l, to said end-cover along a circumferential line radially in whicha much shorter driving-end cover may be used outside of said ventilatingducts, said shell forming with because the impeller is to be operatedcloser to the oven said end-cover a fan housing, a centrifugal fanmounted wall. It will be seen that, except for the size and shape forrotation on said shaft and within said fan housing, of the covers 126and 135, and of the air passages 12% and a second group of ventilatingducts located in said and 132, everything is substantially the same asfor the end-cover, radially outside said first group of ventilatinglonger motor of Fig. l and the basic ventilation arrangeducts butradially Within said circumferential line, wherement has not beenchanged. 35 by the draft induced by said fan causes air to flow intoFrom the above it will be perceived that, according to said fan housingthrough said first group of ducts and out the invention, there has beenprovided, in a motor for of said housing through said second group ofducts. driving a fan in a high-temperature drying oven, a high- 4. In adynamoelectric machine of the open-frame velocity flow of ventilatingair past the driving-end beartype, a first end-cover having air-inletopenings, a rotor, ing, which air is but slightly hotter than theambient a fan formed on said rotor at the end thereof adjacenttemperature because it is guided in such a path that it does sa d firstend-cover, a stator frame, a stator core secured not absorb anysignificant heat directly from the drymg w1th1n said frame, longitudinalventilating ducts formed chamber before it performs its function ofextracting heat in said frame behind said core, a second end-cover offrom said bearing. generally cylindrical shape forming with said dynamo-Having thus set forth the nature of the invention, what electricnrachinean enclosure communicating with said I claim herein is: ventilatingducts and provided with an external flange 1. In a dynamoelectricmachine of the open-frame portion at the end adjacent saiddynamoelectric machine type, a stator frame, an elongated end-coverformed at and with a transverse wall portion at the opposite end one endwith a supporting flange and secured to said thereof, a bearingcentrally disposed in said wall portion, stator frame at said flangedend, a shaft, a bearing for air passages therein surrounding saidbearing and comsaid shaft carried by said end-cover at the end oppositemunicating with the interior of said second end-cover, said flanged end,ventilating ducts formed in said enda rotor shaft journaled in saidbearing, a centrifugal fan cover radially adjacent said earing, animperforate secured to said shaft adjacent to and externally of saidcylindrical shell surrounding said end-cover, secured second end-cover,a casing for said fan, secured to said thereto, and spaced radiallytherefrom to form an ansecond end-cover by a circumferential joint insaid flange nular enclosure communicating with the interior of saidportion, and air-outlet passages in said flange portion disend-cover bymeans of said ventilating ducts, said endposed radially within saidcircumferential joint. cover being provided with an apertured portion adacent said flanged end for providing; commurlilication getwzenReferences Cited 1n the file of thls patent said annular enclosure and te atmosp ere, an a an mounted for rotation with said shaft andpositioned with- UNITED STATES PATENTS in said enclosure, for setting upa ventilating air OW Number Name D t from Within said end-cover pastsaid bearing and re- 1,697,279 Klernm Ian. 1, 1929 versely through saidannular space to tfhe atmosph ,19 ,952 Bogaty Apr. 9, 1940 2. In adynamoelectric mac inc 0 t e openrame M type, a composite end-covercomprising an inner cylin- FOREIGN PATENTS drical portion formed at oneend with a radial flange and Number Country Dat at the other end with abearing support, axially disposed 116,592 Australia F b, 1 1943ventilating ducts in said inner portion surrounding said

